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The emergence of gentamicin-resistant klebsiellae in a large general hospital
Abstract:
Between March and December, 1975, an outbreak of infection with gentamicin-resistant Klebsiella pneumoniae (klebsiella (Gmr)) occurred at the Royal Melbourne Hospital. The klebsiellae were considered to be causing significant infection in 24 of 42 patients harbouring the microorganism. Commonest culture sources were urine and sputum, all but one of the significant urinary infections being associated with indwelling bladder catheters. Antibiotic therapy had been given to 40 patients before the isolation of klebsiella (Gmr), and of these 22 had received gentamicin. Cross infection was a major factor in the outbreak, and control measures (to limit this aspect and curtail the usage of gentamicin) have prevented wider spread within the hospital; at the time of writing the microorganism had been eradicated from all but one of the infected patients. It was shown that klebsiella (Gmr) carry an R-factor capable of transferring gentamicin resistance. Of 22 isolates tested quantitatively, 20 were resistant to 10 mug/ml of gentamicin.
Insights
An outbreak of gentamicin-resistant Klebsiella pneumoniae occurred in 1975. Control measures limited spread, and the resistant bacteria, carrying a transferable resistance factor, were eradicated from most patients.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Hospital Epidemiology
Background:
- An outbreak of gentamicin-resistant Klebsiella pneumoniae (Gmr) occurred at the Royal Melbourne Hospital between March and December 1975.
- This microorganism caused significant infections in 24 out of 42 patients.
- Common sources of infection were urine and sputum, with most urinary infections linked to indwelling bladder catheters.
Purpose of the Study:
- To investigate the outbreak of gentamicin-resistant Klebsiella pneumoniae.
- To identify the contributing factors and implement control measures.
- To understand the resistance mechanism and its transferability.
Main Methods:
- Surveillance of patient infections and microbial cultures.
- Analysis of patient antibiotic history, particularly gentamicin use.
- Investigation of cross-infection transmission routes.
- Characterization of the resistance mechanism, including R-factor transfer studies.
- Quantitative assessment of gentamicin resistance in isolates.
Main Results:
- Cross-infection was identified as a major factor in the outbreak's spread.
- 40 patients had prior antibiotic therapy, with 22 receiving gentamicin.
- Gentamicin-resistant Klebsiella pneumoniae isolates carried a transferable R-factor conferring resistance.
- 20 out of 22 tested isolates showed high-level resistance to gentamicin (≥10 μg/ml).
Conclusions:
- Effective control measures, including limiting gentamicin usage, halted the wider spread of the outbreak.
- The microorganism was eradicated from all but one patient by the time of reporting.
- The presence of a transferable R-factor highlights the potential for rapid dissemination of antibiotic resistance in hospital settings.